package com.yunshang.shoppingmall.common.weixin;

import java.security.MessageDigest;
import java.util.Random;

public class Md5 {
    public static String MD5(String s) {
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            byte[] bytes = md.digest(s.getBytes("utf-8"));
            return toHex(bytes);
        }
        catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public static String toHex(byte[] bytes) {

        final char[] HEX_DIGITS = "0123456789ABCDEF".toCharArray();
        StringBuilder ret = new StringBuilder(bytes.length * 2);
        for (int i=0; i<bytes.length; i++) {
            ret.append(HEX_DIGITS[(bytes[i] >> 4) & 0x0f]);
            ret.append(HEX_DIGITS[bytes[i] & 0x0f]);
        }
        return ret.toString();
    }

    public static String getRandomNumCode(int number){
        String codeNum = "";
        int [] numbers = {0,1,2,3,4,5,6,7,8,9};
        Random random = new Random();
        for (int i = 0; i < number; i++) {
            int next = random.nextInt(10000);//目的是产生足够随机的数，避免产生的数字重复率高的问题
//    			System.out.println(next);
            codeNum+=numbers[next%10];
        }
        System.out.println("--------");
        System.out.println(codeNum);

        return codeNum;
    }

         private final static String[] hexDigits = { "0", "1", "2", "3", "4", "5","6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

 /**
      * 转换字节数组为16进制字串
      *
      * @param b
      *            字节数组
      * @return 16进制字串
      */
        public static String byteArrayToHexString(byte[] b) {
         StringBuffer resultSb = new StringBuffer();
         for (int i = 0; i < b.length; i++) {
         resultSb.append(byteToHexString(b[i]));
         }
         return resultSb.toString();
         }

         private static String byteToHexString(byte b) {
         int n = b;
        if (n < 0)
        n = 256 + n;
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
        }

        public static String MD5Encode(String origin) {
           String resultString = null;
            try {
                  resultString = new String(origin);
                  MessageDigest md = MessageDigest.getInstance("MD5");
                  resultString = byteArrayToHexString(md.digest(resultString.getBytes("utf-8")));
                 } catch (Exception ex) {
       }
        return resultString;
       }
}
